Since then, the bulk of Eminem's freelance work has been via Dr. Dre's Aftermath camp, from Xzibit to 50 Cent's G Unit. He has had mixed success with his Shady Records empire; many of the names on his 2006 comp The Re-Up, like Stat Quo and Bobby Creekwater, subsequently disappeared, but Yelawolf and Slaughterhouse's major-label albums made it to stores. In recent years, Em has mentored pop singer-songwriter Skylar Grey. He occasionally builds with fellow megastars like Jay-Z, Lil Wayne and T.I. It's a rare and pleasant surprise when Eminem drops a verse for someone that doesn't fit these categories, like when he jumped on B.o.B's "Airplanes, Part II." The Detroit icon is the most deliberate of cameo kings; he doesn't make false moves.